elbert :
The 1060 is the fastest but not going to get you any added years. Laptop GPU's have less differance in performance. It really depends on price if the 1060 is worth the extra.
This generation of GPU's is different, They are all desktop class this time around. The biggest difference is that the 1060 3gb is the same chip as the 1060 6gb, just less VRAM, unlike the desktop parts where the 3gb is a cut down chip.
Having a more powerful GPU just helps longevity as it will start at a higher performance point and take longer to slide into obsolescence.